This invention relates broadly to the field of clasps or similar releasable closure devices used in the field of jewelry or other body worn articles, and more particularly relates to such closure devices that are used with body encircling articles such as necklaces or bracelets. Even more particularly, the invention relates to such closure devices wherein the releasable closure mechanism involves a magnetic connection, and to the articles of jewelry comprising such closure devices.
Releasable closure devices for jewelry or similar articles are well known, and when used in connection with bracelets, necklaces or similar body- or body-part encircling articles are often referred to as clasps. The use of a releasable clasp enables the article to be easily put on and removed. Many clasps involve the use of mechanical interlocking mechanisms, such as threaded joints, pin-and-groove combinations, pivoted hooks, spring-biased catches or the like. Because of the small size of the clasps, it is often difficult to connect or release these mechanical locking mechanisms—especially when the wearer is attempting to put on or remove the jewelry without help form another person. In addition, the clasps typically detract from the aesthetics of the jewelry.
Another type of jewelry clasp utilizes one or more magnets as the releasable retention means. The use of one or more magnets allows for relatively easy operation as opposed to the sometimes difficult operation of the mechanical interlocking mechanisms. Examples of known magnetic clasps are shown in U.S. Pat. No. 2,623,256, issued in 1952 to Feibelman, U.S. Pat. No. 3,129,477, issued in 1964 to Mizuno, U.S. Pat. No. 4,901,405, issued in 1990 to Grover et al., U.S. Pat. No. 5,197,168, issued in 1993 to Levy, U.S. Pat. No. 6,640,398, issued in 2003 to Hoffman, and U.S. Patent Application Publication 2004/0154143 of Harrell. While these disclosures show magnetic clasps useable with bracelets, necklaces or like body-encircling articles of jewelry, the performance of these clasps is not optimal with regard to functionality and aesthetics due to their linear configuration in the axial direction when used with body-encircling articles of limited flexibility.
Bracelets, necklaces and the like have physical structures ranging from relatively rigid to non-structured. Relatively rigid articles may be designed as a single, shaped member, usually composed of metal or a hard plastic, with a gap of sufficient size to allow the jewelry piece to be opened a sufficient distance for passage of the neck or wrist, the article having slight flexibility to allow such action without incurring permanent deformation or bending of the article. Such articles do not require clasps for closure. Other articles of a relatively rigid nature may have multiple rigid components joined with only a single or relatively small number of joints or hinges, in which case a clasp will be required to keep the article in the closed configuration. At the opposite end of the spectrum are bracelets, necklaces and the like that are relatively non-structured or completely articulated, such as those composed of chain links or cords, and which require clasps for retention. In between are bracelets, necklaces and the like that are semi-rigid and somewhat structured, such that there is a limited amount of flexibility inherent in the article but the article retains a predetermined circular, elliptical or oval shape when worn. Examples of these articles of jewelry are those made of cables, braids or bundled fibers.
When axially linear clasps are used with semi-rigid bracelets, necklaces and the like composed of cables, braids or bundled wires or fibers formed with a predetermined circular, elliptical or oval shape, the continuity of the circular, elliptical or oval shape is broken by the linear aspect of the clasp. The nature of this type of jewelry typically requires a sleeve or ferrule to be disposed on each end of the looped article to retain the multiple ends of the cable, braid, wires or fibers. When such ferrules are axially linear, the joining of the two ferrules results in the natural curve of the jewelry being disturbed, as the curved components are suddenly directed into a linear configuration at the joint between each of the ferrules and the curved components. This can impart an undesirable bulge or misshape in the jewelry, which can be seen for example in the illustration accompanying U.S. Pat. No. 2,623,256 to Feibelman. This bulge is the result of lateral strain effects inherent in the axial curvature of the semi-rigid jewelry, and the strain at the junction between the looped article and the clasp may result in permanent deformation of the looped article or failure of the junction itself. In addition, if the clasp is of the magnetic type, the lateral strain effects act in opposition to the magnetic attraction forming the releasable connection, thereby weakening the connection such that the clasp is more likely to be accidentally opened.
The use of curved mechanical clasps is known, such as shown in U.S. Pat. No. 856,480, issued in 1907 to Long, U.S. Pat. No. 1,140,445, issued in 1915 to Collingwood, and U.S. Pat. No. 1,807,293, issued in 1929 to Keller. The Collingwood patent shows the use of a single curved sleeve in conjunction with a braided or cable bracelet, such that the natural curve of the bracelet is not altered by the joining component, but this bracelet is stretchable and the ends cannot be disconnected, since the sleeve does not function as a clasp.
It is an object of this invention to provide a magnetic clasp for body- or body-part encircling articles of jewelry composed of cables, braids or bundled wires or fibers having a semi-rigid structural configuration of circular, elliptical, oval or otherwise curved nature, wherein in the clasp is curved rather than axially linear such that the inherent curved shape of the article of jewelry is not altered, disturbed or misshaped.